In the past, as fabrics for printing screens, silk or stainless-steel mesh fabrics have been broadly used. However, the silk mesh fabrics were deficient in the strength and the dimensional stability for a printing screen. As regards the stainless steel mesh fabrics, severe problems were found in the elastic recovery and the instantaneous repelling force when a squeegee was applied. Further, silk and stainless are expensive.
Recently, for the above reasons, polyester or nylon mesh fabrics have been more used for printing screens. Particularly, the polyester mesh fabrics have been more preferred from the viewpoint of the high dimensional stability. However, the polyester mesh fabrics have the following disadvantages:
(a) White-powdery scum is generated during the weaving, which will cause many troubles. PA1 (b) The emulsion-coating properties is low. PA1 (c) For forming a coating film at a constant thickness, skillful techniques and several overlap coatings are required. PA1 (d) The production efficiency is low. PA1 (e) The adhesion of the meshes to an emulsion resin is insufficient. The printing durability is low.
In attempt to solve the above problems, various ways utilizing chemical treatment with acids or alkalies or the like, flame treatment, corona-discharge treatment, and so forth have been examined. However, various troubles such as reduction in the strength of the material and so forth have arised. The test results of the screens prepared in such ways have been unsatisfactory for practical application.
On the other hand, with diversification in the printing fields, high printing precision and high printing durability have been more required. Particularly, it is needed to develop a screen which has a high dimensional stability comparable to that of a stainless-steel screen, a high adhesion to an emulsion resin comparable to that of a nylon screen, and a high elastic recover property comparable to that of a polyester screen.
Japanese Laid-Open Patent Publication No. 142,688 of 1984 discloses an anti-static mesh fabric made from conjugate filaments. The anti-static mesh fabric is characteristic in that it is made from a theremoplastic synthetic polymer added with electro-conductive carbon black. An object of that lies in an improvement in the antistatic property of a screen mesh fabric. However, there is not taught any way for improvement of printing precision and printing durability which have been much desired as described above.
Accordingly, an object of this invention is to provide a mesh fabric useful for a printing screen having high dimensional stability, adhesion to an emulsion resin and elastic recovery property, that is, having high printing precision and printing durability.